Can an underbite be corrected without jaw surgery?
“I have been advised to have jaw surgery. Is orthodontic treatment without surgery possible?”
This is a question we often hear from patients with Class III malocclusion. Some cases of skeletal Class III malocclusion, in which the lower jaw projects forward, require surgery. However, surgery is not necessary for every patient.
By assessing the skeletal discrepancy, the way the teeth fit together, the limits of the supporting bone and the degree of change the patient wants, we may find that orthodontic treatment alone can provide improvement.
This case describes non-surgical underbite treatment with Invisalign for a woman in her twenties who came to us with an anterior crossbite and prominent lips.
Before treatment
The patient had previously been advised to undergo jaw surgery but wanted treatment without surgery if possible.
A detailed examination showed a skeletal Class III relationship with a forward-positioned lower jaw, as well as an overall Class III relationship between the upper and lower teeth. The front teeth were almost edge-to-edge. However, because the lower front teeth were tilted inward, straightening them could have made the anterior crossbite more pronounced.
She also showed a tendency toward a long facial pattern and an open-bite pattern with insufficient overlap of the front teeth, along with a prominent lower lip. The upper right second molar had erupted downward, and the wisdom teeth were impacted within the jawbone.
Simply tilting the front teeth to make them meet would therefore not have been enough. We needed to move the entire lower dental arch backward to improve the Class III relationship, while preventing unwanted extrusion of the back teeth and controlling the vertical position of the front teeth so that the long facial pattern and open bite did not worsen.
Treatment plan: moving the lower dental arch backward and controlling vertical tooth position
We used Invisalign Comprehensive for treatment.
We could also have considered MARPE, a miniscrew-assisted palatal expansion appliance, to widen the upper jaw. However, the patient felt considerable concern about the additional miniscrew-based expansion treatment. After discussing the advantages and limitations of each approach, we agreed to prioritize improvement of the anterior crossbite and open bite within the range achievable with Invisalign.
First, orthodontic miniscrews were placed in the lower jaw, and Class III elastics were used to help move the lower dental arch backward. The molars were moved sequentially to create space for retraction of the front teeth.
In this patient, the Class III malocclusion and open bite needed to be considered together. Unwanted extrusion of the back teeth can rotate the lower jaw downward and backward, making the face look longer and worsening the open bite. We therefore limited extrusion of the upper and lower posterior teeth while adjusting their vertical positions as needed.
At the same time, appropriate extrusion of the upper front teeth was planned to increase their visibility and create a natural overlap between the upper and lower front teeth. Rather than relying on a single approach, such as indiscriminate molar intrusion or extrusion of the front teeth alone, we coordinated backward movement of the lower dental arch, prevention of posterior extrusion and extrusion of the upper front teeth.
Invisalign can be useful in cases that require both front-to-back movement and control of vertical tooth position. However, actual tooth movement can differ from the plan, so checking the bite during treatment and making adjustments with additional appliances are important.
During treatment · Side view of the teeth
Treatment involved three courses of aligners over two years and two months
Treatment lasted approximately two years and two months, from April 10, 2023, to May 7, 2025.
- First Invisalign course: 44 stages
- Second Invisalign course: 21 stages
- Third Invisalign course: 9 stages
After the first course produced the overall tooth movement, two additional Invisalign courses were used to refine the overlap of the front teeth and the fit of the molars. In complex skeletal malocclusions, treatment often requires reassessment of actual tooth movement and staged refinements rather than completion with the initial plan alone.
Treatment results: improvement in the anterior crossbite and lip protrusion
After treatment, the reversed relationship of the front teeth was resolved, and positive overjet and overbite were established, with the upper front teeth naturally overlapping the lower front teeth. Overjet and overbite, both 0 mm before treatment, improved to approximately 1.5 mm each.
As the lower dental arch moved backward, the prominence of the lower lip also decreased. By limiting unwanted extrusion of the posterior teeth and adjusting the visibility and position of the upper front teeth, the smile line improved, along with the appearance of the lower face, which had looked elongated in association with the open bite.
The teeth were aligned, and the overall relationship between the upper and lower teeth improved. However, because MARPE was not used, limitations remained in the width and fit of the canines and some posterior teeth. This reflected the decision to prioritize correction of the anterior crossbite and a stable front-tooth relationship within the scope of treatment the patient was willing to accept.
Non-surgical underbite correction does not reduce the size of the lower jawbone itself. It aims to improve the bite, lip line and facial appearance within the limits permitted by the teeth and their supporting bone.
Retention after treatment
After active treatment, fixed retainers were bonded to the inner surfaces of the teeth, and Vivera removable retainers were also used. The bite and alignment remained stable through approximately three months after appliance removal, although continued long-term observation is needed.
Accurate diagnosis guides non-surgical underbite treatment
Not every skeletal Class III malocclusion can be treated with Invisalign alone. If the skeletal discrepancy or facial asymmetry is substantial, or if the changes the patient wants involve the position and shape of the jawbones themselves, treatment combined with surgery may be more appropriate.
Conversely, if there is sufficient scope for movement within the teeth and supporting bone, and tooth movement can produce the desired changes in the bite and facial appearance, non-surgical underbite treatment with Invisalign may be considered.
The goal is not simply to avoid surgery. It is to distinguish skeletal limitations from achievable changes before treatment and create a stable bite within safe limits.
Photographs taken: April 10, 2023 – May 7, 2025
※ The results shown in this case may vary depending on individual skeletal anatomy, dental and periodontal condition, and adherence to appliance wear and elastic use. The appropriate treatment approach should be determined through a detailed examination and diagnosis by an orthodontic specialist.
References
- Padmanabhan A, Khan Y, Lambate V, et al. Efficacy of clear aligners in treating Class III malocclusion with mandibular molar distalization: a systematic review. Cureus. 2023;15(11). doi:10.7759/cureus.48134.
- Correa E, Michelogiannakis D, Barmak AB, Rossouw PE, Javed F. Efficacy of clear aligner therapy for the treatment of anterior open bite in adults: a systematic review and meta-analysis. Orthod Craniofac Res. 2025;28(2):261-270. doi:10.1111/ocr.12868.
